The act of spitting the cum that your partner unexpectedly deposited in your mouth back in his mouth. Some people may like this, but, in general, it is thought to be an act used to get back at a guy for cumming in your mouth without warning.

He came in my mouth without any warning, so I snow blowed the punk to get him back.

The act of getting back at someone for cumming in their mouth and not telling them. (I.e) After cumming in someones mouth that person then with out telling you, spits the spermies back into your mouth.